Automatic gun



March 29, 1938 I F. HUDSON AUTOMATIC GUN 7 Sheets-Sheef 1 Filed June 26,1929 m m- N 3 mm V, cm NR L L y m a N 6H0: an

March 29, 1938. R. F. HUDSON AUTOMATIC GUN Filed June 26, 1929 7Sheets-Sheet Z Haber/ F Hudson March 29, 1938. I R. F. HUDSON 2,112,660

I AUTOMATIC GUN Filed June 26, 1929 '7 Sheets-Sheet 4 Rober/ F HudsonMarch 29, 1938.

Filed June 26, 1929 '7 Sheets-Sheet 5 O) 2 LL gnmbtoz Baber/ F Hudson Maflo'zucq mm 0 I1 a s 3 a a III I III,

"a VII/I IIIIIIIIIIA March 29, 19

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AUTOMATIC GUN Filed June 26, 1928 7 Sheets-Sheet 6 m J H M F a 1w a b#0E buLa chu R. F. HUDSON AUTOMATIC GUN Marizh 29, 1938.

Filed June 26, 1929 '7 Sheets-Sheet 7 gmwnfo'o Roberf F Hudson PatentedMar. 29, 1938 The present gun is a gas set, mechanically op= erated,automatic gun, the power for operation being obtained by passing aportion of the pow= der gases into a gas cylinder for the purpose ofcompressing a main spring in a forward direction, the energy stored inthe main spring being used to serve the poses of unlocking, driving thebolt and attached parts of the mechanism to the rear, and forcompressing the bolt spring. This gun, similar to any automatic gun,must be retracted by hand in order to load the first cartridge into thechamber. After the first cartridge has been loaded, the triggerreleased, and the cartridge fired, the automatic action starts. The boltspring, which has been compressed during the rearward movement, returnsthe bolt and attached mechanism forwardly, provided the trigger ispulled .to prevent the retracting catches from holdin'g the mechanism tothe rear. During the rearward movement the cartridge guide and electorsare held in the housing by the bolt until the bolt clears'them andallows the ejectors to be forced out of their housings by the ejectorsprings, so that the ejectors strike the fired cartridge case above thecenter line, which causes the fired case to be driven from the face ofthe bolt and out of the receiver.

When the cartridge is fired, a portion of the powder gases are permittedto enter the gas cylinder and drive the piston forwardly, whichcompresses the main spring, the surplus energy from the powder gases inthe gas cylinder being transmitted to the buffer by a positive linkwhich connects the gas piston and the bufling element at the forward endof the main spring housing. The gas used from the barrel is tapped at apoint of maximum pressure, maximum temperature, and where the velocityis still increasing.

It will be found from the art of using gas power for operation, eitherdirect or indirect, that two basic and distinctly different methods ofoperating are available. First, if advantage is taken of the maximumenergy available from a portion of the powder gases, it must be taken ata point where the ordinate of thepowder curve is a maximum, and it mustbe used with a powder that will retain this maximum value of theordinate through a considerable portion of the curve. This means that aprogressive burning powder is necessary to obtain the maximum advantageto be gained when the gases are to be used at a point of maximumpressure, maximum temperature and one at which the velocity is stillincreasing.

The other distinct method or using powder gases for operation or themechanism, or for counteracting the base pressure, or recoil, must usetheonly remaining source, i. e., the velocity of the powder gases mustbe taken advantage of, which naturally indicates that this can only beaccomplished at or near the muzzle of the gun. At this point, theordinate of the powder curve is a minimum, which shows that the energyavailable is spent at the sacrifice of an increase in velocity. Thisbeing the case, apparently advantage must be taken of the maximumvelocity to further counteract the base pressure or recoil. This may beaccomplished by providing a socalled muzzle brake, which may consist ofbaffies, deflection plates, or slots, or any other means of checking thevelocity of the powder gases to utilize the energy available from thegas, at or near a point of maximum velocity. The powder curve ordinatebeing a minimum, shows that the energy available, due to temperature andpressure, cannot be used at this point. The total energy available fromthe powder gases, their period of application, the time of theapplication of base pressure, or recoil, has been thoroughly analyzed.

The present automatic gun has been designed to specifically utilize thetotal energy available, by coordinating the time of application as nearas physically possible to coincide with the period of application of thebase pressure, and advantage is taken of the position of the maximumordinate of the powder curve by taking off the operating powerimmediately after the maximum ordinate has been reached. This also givesthe maximum period of application of the greatest energy available overas long a distance of bullet travel in bore as is possible. Theapplication of the maximum energy available is dissipated in terms ofstored operating energy, the excess is absorbed in a forward directionby a buffer means. The bullet is still in the barrel during this periodof application, due to the application of the energy to the gas pistonimmediately after the maximum ordinate of the powder curve has beenreached. The maximum ordinate, or a mean maximum ordinate, is sustainedwith a progressive burning powder for more than onethird the distancetraveled by the bullet in the barrel, and, therefore, the energy storingmeans has coacted and relayed its energy to the bufling element duringthis time. The bullet leaves the barrel along with the powder gases atthe maximum velocity obtained in the barrel, with the pressure. minimum.The muzzle brake or velocity dissipater, whether it be a reflectionmechanism or retracting mechanism does not matter so long as advantageis taken of maximum velocity of the gas which emerged from the muzzleunit at a greatly reduced velocity, can serve only .to reduce recoil,due to the arresting of the forward velocity of the powder gases. r e

What would appear to be a fine. distinction between the presentautomatic gun and other automatic guns, using a portion of the powdergases for operating directly or indirectly, is, in reality, a verydistinct difference, and has the same parallel as two moving objectsracing each other in opposite directions.

The gas piston of the present type of automatic gun travels a distancegreater than the length of the cartridge in a forward direction with nomechanical connection, or any other type of com-v munication between thegas piston and the bolt mechanism. In fact, during this forward movementof the gas piston, and the bullet travel in the barrel, no part of themechanism of this gun moves to the rear, and the only reaction in therearward direction is the base pressure on the cartridge case itself.The object of the gasesand piston moving forwardly from first thought,.will not be apparent to either the layman, engineer, or gun expert. Thefirst advantage of prime importance is the delayed action, i. e.,allowing the bolt and breech lock to remain locked against the firedcartridge, with no linkage whatsoever to start the unlocking until aconsiderable period has elapsed after the bullet has left the gun. Thisinsures the dissipation of the entire base pressure in the firedcartridge case so thatno strain is placed on either mechanismorcartridge case when extraction is performedx This also assures apositive sealing of-the chamber which reduces erosion of the bulletseat, and the mech anism of the bolt; theprimer is firmly supporteduntil all pressure has left the cartridge case; and no leakage aroundthe primers can occur, a most serious defe'ct found with other automaticguns in general. The main disadvantage with leaky primers is the highlyerosive efiect of the primer gases on the face of the bolt whichdestroys the usefulness of the bolt, the most expensive component ofautomatic guns. Leaky and blown primers are a source of endless troublewith automatic guns. In automatic guns in general, this condition isgreatly aggravated by attempting to extract the fired cartridge casebefore the pressure in the case has been eliminated or dissipated.

Again, it might be apparent, on first thought, that the selection of theport for tapping the gases from the barrel should be at a point ofmaximum pressure and maximum temperature. The art does not show this,and until a very recent date the art could not have shown this, as noprogressive burning powders were available, and were not availableduring the period of development of a single automatic weapon,regardless of caliber, in use at the present time by any country in theworld. It was only natural, in the analysis of present-day requirementsfor an automatic gun that this most important factor should havereceived serious consideration. It is well known in the art that thepowder curve for quick burning powder, which was the only powder inuniversal use until a very recent date, has a maximum ordinate, a veryshort distance from the breech of the barrel, and which diminishes mostabruptly and is practically spent as to pressure and ordinate valuebefore one-fourth the length of the barrel has been reached.

vantage to be obtained with energy available from the powder curve of aprogressive powder, the analysis was continued to determine the energythat should be taken from the energy available from the powder charge,without diminishing the available energy under the powder curve. 7

The second consideration naturally followed to determine thepoint atwhich the gases should be tapped in order to have the gases delivertheir energy to the piston and communicate it to the counterrecoilbufllng elements. This point hav ing been determined, namely, the pointat which the. maximum ordinate appears on the powder curve, less thedimension forwarded on the power curve found necessary to handle theheat effect from the powder gases, it. still had to be deter- -minedwhat" timing was necessary to insure that the counterrecoil-element(which is an energy dissipating element acting in a forward direction)was sov applied that it would be co-acting with the base-pressure (theelement which contributes to the recoil of the gun). This was determinedand verified and the counterrecoil restraining members were calibratedto withstand twenty-five percent. less energy than is exerted by thecounterrecoil elements. The acid test is: Will the breech lock remainlocked after the restraining cap is broken, or will it unlock'before thecap is broken? Should the breech remain locked, it would mean that thebase pressure (recoil source) would have been exerted, and the freerecoil found would be approximately the equation shownbelowzn C=Weightofv powder charge W=Weight of gun P=Weight of bullet V=Velocity ofbullet VF=Velocity of freerecoil were co-acting for the reason that theenergyused' in the counterrecoil element is very similar in comparisonto that available in the borelof the gun. Again, the weight of the partsof the counterrecoil element that has moved in a forward direction isroughly times the weight of the bullet, so it can be seen that velocityacquired by these parts is extremely low as compared to that acquired bythe bullet; and'yet, the velocity of the counterrecoil parts moving inthe forward direction will be more than 10 times the velocity acquiredby the mass of the gun tending" to move in the rearward direction due tothe base pressure, as the ratio of weight of the counterrecoil partsmoving ina forward direction to the weight of the gun is less than 1 to40.

It can be readily .seen that atremendous ad vantage is to be gained asthe velocity contributes ordinate and highest temperature, as wellasmaximum pressure, and when the velocity is increasing, makes availablea temperature-pressure energy component acting in a forward direction,which is dissipated in the forward direction.

This unit is utilized as part of the counterrecoil element as thevelocity is relatively lower. A dissipation of the temperature andpressure results in an energy component in the forward direction whichalso is co-acting with the base pressure exerted in the oppositedirection. The energy used for counterrecoil must be coordimated withthe time of application, nature of application, the heat and pressure tobe dealt with, and coordination with the utilization of the velocitycounterrecoil unit, which is distinct and apart from thepressure-temperature unit, of counterrecoil, but is so closelyassociated with and 'co-acting that the total counterrecoil availableand base pressure must be considered together when the maximumcounterrecoil is to be expected.

From the foregoing, a clear distinction can be seen between this newtype of gas energized mechanism, mechanically operated, and theconventional existing strictly gas operated automatic guns. Theconventional type not only develops the hammer blow as its operatingcomponent, but exerts this hammer blow at the most critical time ofoperation so as to create the greatest disturbance to offset stabilityand, in addition, adds to the recoil of any automatic weapon.

It can be readily seen that when a piston is caused to be driven to therear it must be arrested, whether it be arrested through a toggle link,a buffer, or both. This is bound to be coacting with a base pressure inthe same direction. or otherwise the gun would not operate. To verifythis, it is only necessary to fire a very few shots from an automaticrifle which will demonstrate the inability of the marksman to hold therifle on the target, due to this gas operating element being driven tothe rear and returning with the same disturbing effect, as the returnoccurs after the pressure or recoil has reduced and caused the gun to bedisplaced below the normal aiming point, whereas a movement to therearcauses a disturbance above the aiming point. Again, one of the mostdisturbing'efiects is the fact that automatic fire builds up-the recoiland is actually greater after the seventhor eighth shot is fired thanwhen the first shot is fired. This is true for the direct acting gasoperating guns due to the fact that all direct acting gas operated gunsdo not dissipate the recoil between each shot. The blow exerted tooperate the gun, therefore, is not dissipated for each shot,as thedissipation can only be acquired with a decided delayed action and withthe operation element exerting a forward force and not a backward force.I e

Another consideration is the offsetting of the disturbing effects ofrecoilingand counterrecoiling units of the gun. To accomplish this,automatic guns of the past have used steep ramps or cams for braking theenergy stored in the parts, which, in some cases, arecombined with thelocking' element, This phase of automatic guns has been thoroughlyanalyzed and, in'the present gun, steps have been taken to overcome thismost serious defect.

The arresting of the recoil and counterrecoil parts with the line ofaction a considerable distance from the bore of the gun is entirelyovercome in the present gun by the provision of a power storing means sothat the gun can be operated mechanically,

advantage having been taken of the mechanical operation to disconnectthe operating power to overcome the hammer blow exerted with recoilbarrels, and it is also disconnected after the full stroke is completed.The surplus energy necessary to insure operation under variable frictionconditions clue to temperature, lack of lubrication, dirty mechanism,defective ammunition. burrs, etc., is not absorbed by a bu fling elementwhose application or action line isa considerable distance from the axisof the bore, but is absorbed by a bumng element directly connected tothe barrel, placed in as close proximity as possible. In the firstplace, this reserve energy is cut to a minimum as it is not necessary tostore sufiicient energy to return the barrel to battery or to returnelements to the forward position that have any appreciable weight in thepresent gun. This is a most important factor when automatic guns arefired at an elevation. Again, the mechanical operation, as against theaction of a blow, insures uniform regulated speed of fire of the gun.The necessity for locking and unlocking the breech lock with a steepangle is eliminated as the locking means is not used in the present gunfor braking the recoil or counterrecoil force. Indeed, the reverse istrue, as the locking element is not used for arresting the recoil andcounterrecoil force. It is actually cushioned to overcome any tendencyto lock and unlock with a harsh or blow action. This feature alone,makes it possible to use a very fiat angle of locking, an angle slightlyabove the friction angle, whereas all automatic guns in existence use anabrupt angle of 40 or more, which not only exerts unnecessary strains onthe mechanism, but disturbs stability of the mechanism and causesexcessive wear and breakage of parts. In the original study and analysisof the specifications of the present automatic gun, an exhaustiveinvestigation was made of the methods of presenting the breech lock tothe locking recess in the frame. The best comparbe summarized asfollows:-

To provide a lock which will be locked with the least shock and yet bepositive. To have the lock travel as near as possible at the samevelocity at the time of looking as that of the bolt, and to have thelock take up the velocity of the bolt just before and during unlocking.

Practically all automatic weapons in existence use a breech lock that isentirely stationary, or one that is moving with an extremely lowvelocity as compared with the velocity of the locking element with whichit mates.

In the present gun, the breech lock is carried with the bolt. Theparallelism is exactly the same as would be encountered in moving agiven weight, a definite height on a high speed train, as compared withthe same weight moved the same height by the same person attempting toraise it from a mail-bag arm. Some automatic weapon designers resort toa method of locking by rotating the bolt after it has reached itsforward position. While this method has some ad- 'ison of the trend ofthought on this subject can vanti' ges over tl te method of lockingastationary-g-breech lock, it has-a disadvantage in that it jis'necessary' to overcome the energy of translation before energy ofrotation can be accomplished- To do this, the locking angle must beextremely'steep to break the force of the damaging eflect'jhat would beencountered in atagainst the cartridge, the breech lock, in attempt-ving to continue its path, gains the forward face of the breech lockguide of the'bolt, which'is m the position to present the breech'lock'to'the' locking recess against its'forward face, and not its rear face.To prevent pinching or wedging and to insure positive locking in case ofan oversize cartridge, the rear face of the breech lock and of thebreech lock recess are provided with. a

slight angle to give clearance in locking and to obtain wedge actioninthe flnal stage of locking. Furthermore, the advantage to be gainedwith a flat angle of the locking'carn is that the resultant of thislockingeffort i's more nearly parallel with the base pressure and,consequently,'is not a disturbing elementv as to stability. The lockingelement of the present automatic gun is a most powerfullocking means,yet a locking element that requires the least locking .eflfort, thusmaking it possible, and n i g has been taken of this, to cushion.thelocking element. 1

' the action-of the'mainspringj; The frog is the v driven member, themain, spring is the driver, and

the piston rod. The rear'endof Qthe pistonIr'od -In analyzing the'preliminary design of the present automatic gun, serious considerationwas given tothe eifects of they carrying and carried .parts.; When thegun is flred,,-the' gas piston I carrying the cross-head and clutchcompresses the main spring and is finally-arrested byv the counterrecoilbufling element. No part of the receiver mechanism is in motion duringjthis reached its forward position; the' clutch engage which isagainstthe frogtransmits the energyl of the main spring to the-frog whenthefrogi' moves to therear, the bolt-an 'jbreech lock .as a unit arecarried to the rear'by the frog under.

the breech .lock iscamrned-jdown and heldfin the: depressed position, astheretarding effort, 1'

of the bolt tends to keepthe breech lock in its; lower position. vAs thebolt is driven'to the rear,"

'theboltsspring is compressed and the bolt and:

frog'are'finally,arrested-byfthe action of the f regulating "buffer.Thei regulating buffer can be,

throttled tog'overn the rate of r e'coil as the main spring exerts aconstantlyfapplied,iforce which Y is distinctly differentfrom'th'eblow'rebeived by the bolt element of a directly gas operatedgunor a operated from a b ow transmitted bya reiqlling hamll i m ides nextreme simple-speed regulating,;absorbing elementfl.f

In seth er-is pulled. ,andreleased,.'a

single' shot can be fired, either withtlie m ch nism held in theretracting position,'= or Iwith the" mechanism closed on a':cartrid'ge;=,as'desired This featureis verydmportant, 'fa's noautomatic. gunx provides both an' automatic 'Iretracted arrester and aclosure on a' cartridge withoutflfir ing. This feature is also ofextreme importance .to continue the fire immediately without mechanicalmanipulation. When thefbolt has reached the rearward position and thetrigger is held pressed, the bolt becomes the driver under the action ofthe .bolt spring, and the frog the driven member.

When the cross-head, which. carries the clutch, reaches its rearwardposition, the clutch disengages when the clutch pawls come in contactwith'the front face of the frame. I This permits. the cross-head and thegas piston to move to the rear position ready for the next shot, at thesame timeeliminating the necessity of re+ turning the clutch to theforward position by the bolt spring, which spring performs this functionwith a majority of the present automatic gunsf The inertia of the frog,when returned by the bolt, causes it to lag behind the bolt whichmaintains the breech-lock in the lowest'position, eliminating anyfriction drag of the breech lock which would be encounteredif anytendency to lock were present. The frog in going forward, returns thepiston to the forward position through the cross-head, the clutch havingbeen cleared by the clutch pawls.

' T'I'he present automatic machine gun has been provided with a simplebut highly efficient safety. It is of extreme importance when firing.larger caliber shells with supersensitive fuses, and of equal importancewith any caliber, thatthe gun shell, or portion thereof into thechamber... The same isfltrue should a cartridge be fed intothe chamberahead of the bolt, T-slot, or extractor, e and; consequently, fail tofire The bolt must be part of the cycle. When thejcross-head has,

retractedfito. clear-such a jam. This retraction 11 the chamber, wouldbe disastrous-results} With the present automatic orni'allyfeeds thenext cartridge into alignment th .the 'bore. I Inv the case, of asolidshot,'t'h e rimerfof the live round in "the chamber will firedwithvno'supportfor the base of the cartridge to prevent anexplosion withill consequences, re-' 'sulting inpthedestruction of thegun crew and gunshould asupersensitive fused cartridge be machine'fgun', thesafety-block" operates to' prev'enti'thi's accident. [The safety blockcovers'a portion o'f 'the c'hamberat all timesfwhen the 'ichamber isempty." Consequently, any obstructio'n inwthe'chamber, such as a shellorfcartridge', willforce the safety block down, -which raisestherear-end of the safety lever, thus engaging the bolt on the rearwardstroke and arresting the bolt, 'which prevents'the feeding ofanothercar-wf triage. until the chamber hasbeen cleared, Nat'-. I

urally, thesafety block, does not act when I the gunis functioning nomallrjas the bolt itself clears'the obstruction and allows the safetyblock toraise and lower thejsafety lever outioffthe' pathiof the lug ofthe bolt. Bycarrying the breech lock. with the bolt, two

additional safety features aremade possible. One

is .an extension on the, upper portion of; the 75 f breech lock thatstraddles the firing pin head. This extension is provided with arecessed slot, which positively prevents the firing pin from strikingthe primer until the bolt is completely locked and, in addition, servesto move the firing pin to the rear, clear of the primer recess made bythe firing pin, immediately after unlocking begins. In addition, itpermits the separation of the sear and sear carrier unit, and causeseach to operate separately, yet both depending entirely on thecompleteness of the locking of the bolt for their release. This designalso permits the looking to be accomplished directly in line with thebase pressure, as contrasted with the existing types which lock aconsiderable distance below the actual line of the base pressure andcreate a turning moment, which disturbs stability.

The counterrecoiling element of the present automatic machine gun takesadvantage of new discoveries made in this field and coordinates thesediscoveries into a simultaneous co-acting couple. The velocity brake atthe end of the muzzle is not new as to the killing of the velocity toobtain reduction in recoil. However, what is entirely new in this fieldis a mechanism so constructed as to present the gases in a uniformlydistributed way to the bathing elements so as to obtain the maximumrecoil reducing effect, and at the same time to provide a mechanism thatwill not be obstructed with carbon or residue or other'deposits from thefiring, and one in which no disturbing force is presented to make thegun unstable, to defiect gases, or direct intense noise and powder gasesinto the path of the personnel operating the gun.

To provide a stabilizer, in this instance, a central tube is used toovercome the present distortion of the bullet due to the unequaldistribution of gases about the base of-the bullet, present in allexisting recoil muzzle checks, whether they be spiral baflles, directionslots, expansion or contraction chambers with other corresponding escapevents. Some investigators go so far as to claim that these muzzle brakesor recoil checks stabilize the gun by a positive reaction in one or theother direction. The answer to all of this is to so design a successfulautomatic weapon that the entire action and reaction shall be in one-andthe same straight line, as a most efficient application of any force isthe one applied directly in line with the resistance to be overcome withno deflection in the force arm. The forward pull of the muzzle recoilreducer in the present instance acts in this direction.

With the foregoing and other objects in view, which will appear as thedescription proceeds, the invention resides in the combination andarrangements of parts and in the details of construction hereinafterdescribed and claimed, it being understood that changes in the preciseembodiment of the invention herein disclosed can be made within thescope of what is claimed without departing from the spirit of theinvention.

In the accompanying drawings:-

Figure 1 is a side elevation 01' the complete gun made according to andembodying the present invention, the tripod or mount not being shown,and the water or cooling jacket also being eliminated.

Figure 2 is a top plan view of the rear end of the gun, the barrel beingforeshortened.

Figures 3 and 3" constitute a longitudinal central sectional viewthrough the receiver portion of the gun and a portion of the barrel,with the parts in the position they assume just after the firing of thecartridge and the setting of the power spring of the gun.

Figures 4 and i are views similar to Figures 3 and 3 with the parts inthe position they assume at the fully retracted movement of the breechblock and during the ejectment of a spent cartridge from the receiver,and just prior to the introduction of a new cartridge into the breech.

Figure 5 is a rear elevational view of the breech end of the gun.

Figure 6 is a section taken on line 6-6 of Figure Figure 7 is a sectiontaken on line '|'I of Figure 3.

Figure 8 is a section taken on line 8-8 of Fi ure 3.

Figure 9 is a section taken on line 99 of Fi ure 3.

Figure 10 is a section taken on line Ill -l0 of Figure 3.

Figure 11 is a section taken on line ll-ll of Figure 3 Figure 12 is alongitudinal sectional view taken on line i2-l2 of Figure 7, and on linel2'l2' of Figure 8.

Figure 13 is a section taken on line Iii-l3 of Figure 10.

Figure 14 is a section taken on line ||i4 of Figure 8.

Figure 15 is a view similar to Figure 3 of the receiver end of the gun,showing a modified searactuating and operating mechanism.

Figure 16 is an enlarged detail view of the searactuating mechanism inthe position it assumes after just releasing the sear.

Figure 17 is a section taken on line li-ll of Figure 15.

Figure 18 is a section taken on line l8l8 of Figure 15.

Figure 19 is a sectional view through the receiver showing the manualreleasing sear-actuating mechanism in normal position.

Figure 20 is a similar view showing the mechanism in the position itassumes when retracted and prior to the release thereof.

Figure 21 is a detail longitudinal sectional view through the muzzledissipater.

Figure 22 is a section on line 22-22 of Figure 21.

Referring to the drawings, in which like reference numerals representsimilar parts throughout the several views, and in which, in Figure 15,the primed reference numerals represent similar parts as shown inFigures 3 and 4, the numeral I designates the barrel proper of thepresent gun and 2 the receiver. The gun is supported by means of thetrunnions 3 and the yoke 4 on a tripod T and is supported at its rear bythe lug 5 and theadjusting screw 6 operated by the elevation controlwheel I. The present type of gun is also constructed to be mounted uponany form of mount, as it can be used as a tank or antitank gun, as wellas an aircraft or anti-aircraft gun.

A magazine 8 is adapted to feed the cartridges C into the receiver, andalthough here shown as a casing, the same is indicative of a belt feedmechanism. The barrel 9 is fitted into the supporting portion 6! of thereceiver, as at l0, being provided with the breech II for the receptionof the cartridge C, the cartridges being fed into the receiver throughthe opening i2.

A breech block l3, which is capable of straight line reciprocatingmovement within the receiver and is mounted for sliding movement betweenthe strips I4, is also provided with the oppositely disposed end guidinglugs l6. Mounted within and carried bodily by the breech block is thefiring pin ll which is normally propelled forward by the spring l3 sothat the fulminate cap-engaging end l3 may be projected through theopening 20 of the breech, block to engage the fulminating cap of theheld cartridge C. The rear end of the firing pin is adapted to beprojected beyond the rear space of the breech block so that its head 2|willbe in the path of and be automatically engaged by the shoulder 36 ofthe automatic sear 33 which is mounted for vertical sliding movementwithin the recess 32 of the receiver and is held downwardly in place bymeans of the spring 34 and the cap 35.

Also associated with and carried by the breech block are the cartridgeextractors 22, the forward ends 23 of which are disposed forwardly ofthe breech block for engaging the rim of the cartridge C while the sameis within the breech and to be automatically actuated to withdraw thesame upon the rearward movement of the breech block, so that when theempty case is alined with the members 24, as viewed in Figures 8 and 14the portions 24" thereof will be projected outwardly and above the caseto cause the same to be ejected from the receiver. These members 24 aremounted in the oppositely disposed casings 25 and are normally heldoutwardly inthe path of the breech block by means of the springs 26, theforward movement of said breech block retracting said members within thecasings, while the rearward movement permits the springs 26 to act asabove set forth.

The breech-block is provided with the lug 21, the purpose of which willpresently appear, and with the open depending member 28 whichconstitutes a guide for the lock 23 and is of vast importance. The lock23 is provided with the abutting portion 30 disposed to be placed, atthe proper time, between the rear end of the breech block and theportions 30 of the receiver so as to momentarily lock the breech blockagainst rearward movement and during the engagement of thesear-releasing device 3| can'ied thereby, which, as shown, is adapted toenter the opening 32 and elevate the automatic sear 33 so that theportion 36 thereof is moved out of engagement with the head 2| and,consequently, release the firing pin simultaneously with the finallocking position of the bolt. Thus, it will be seen that the lock 23 iscarried bodily by the bolt or breech block in its reciprocating movementand is only brought into locking engagement shortly after the retractionof the firing pin by engagement with the automatic sear 33 and therelease thereof for exploding the fulminating cap. 7

To assist in the forward movement of the breech block, a casing 36, openat one end, is held within the member 28 by means of the lock nut 31,and bodily disposed within this'member is a 7 tube 40 provided at itsfree end with the plunger or piston 4| fitting within the cylinder 42fixed at 43 to the rear end 44 of the receiver.

Mounted within the telescopic members 40 and 42 is the auxiliary spring45 which acts to move the breech block into breech-closing and lockingposition, the same being abutted by the shoulder I; carried by the guidepin 41 and housed within the casing 46 detachably connected at the rearend of the receiver and upon the end 43 of the sleeve 42.

Mounted within the casing 46 is a plunger 43 which is held forwardly bymeans of the spring 50, while mounted for adjusting the rod 41 is amilled finger wheel or button 48, the purpose of which will presentlyappear.

Connected to the barrel 3 forwardly of the receiver is a band 5| which.as shown, has secured therein the rear end of the cylinder 52, and has aport 53 leading from the bore of the barrel 3 into the rear end of saidcylinder so that the gases issuing therefrom act upon the piston 54 tomove the piston forwardly, the purpose of which will presently appear.This piston 54 is connected to the forward end of the rod 55 which isthread edly engaged at 56 to the cross head 51 slidably mounted andguided by the barrel 3 and'the guide rod 53, said guide rod 53 beingmounted throughout the opening 58 of the cross head 51 and attached, asat 66, to the member 5|. The rear end of the rod 53 is mounted in thesolid portion 6| of the receiver and the entire mechanism at this pointis surrounded by a casing 62.

As shown in Figures 3",8Ild 10, the forward end of the rod 61 isconnected to the cross head 51 in an unusual manner, there beingdisposed in the bore 63 the inwardly moved blocks 65 whose springs 65engaging theblocks 64 hold the inner ends thereof in the path of the rod6'! to be en:- gaged thereby, the purpose of which will presentlyappear. The ends 66 of the lock 65 are disposed, as shown in Figure 13,to abut the end of the rod 61, and attached to this rod are the two pins68 which slide within the openings 63 of the bifurcated members 10.

Attached to the rear end of the rod 61 and adapted to be movable withthe same at all times is a link R carrying a setting pin I2 and abifurcated end 13, each member of which is provided with the angularrectangular recess 14, and a sear 15. A pin 1'! is mounted in thelocking block 23 and is engaged at its ends by means of the rectangularblocks 16, said blocks 16 being mounted within the openings 14 so thatwhen the link R is 'reciprocated, vertical reciprocating movement isimparted to the locking member 23.

In order to pull the link R and-also the breech block |3 rearwardlyagainst the action of the spring 45 to initially set the presentmechanism before the first cartridge is fired, the rod 13 is r pulledmanually rearwardly through means of the eye 13 so that the hookterminal 80 will engage the pin 12, the same being pulled until thecatch 15 engages the trigger 8|, at which time, the breech block andmechanism is locked in full rearward position and the spring 45 isplaced under tension. The trigger 8| is mounted within the casing 82formed at the rear under side of the receiver and is itself providedwith a recess 63 for the reception of the rounded end 84 of the triggeror hand-operated member 35 mounted on the pin 86 at the upper portion ofthe hand guard 8'Iand in ready access to the operator of the presentgun.

Connected to the forward end of the rod 55 is a rod 83 which is mountedto move within the forward extension 30 of the cylinder 52 and against.the action of the spring 3| to abut, at the final 'member 83 is takencare of by the buffer 32 at the extreme engagement of the piston 54 andjust Gil imer the escape of the gas through the openings 80 (Fig. 3).

Mounted within the receiver to be engaged b the projection 21 of thebreech block is a pivoted lever 94 mounted upon the pin 95 within thereceiver and provided with the rear weighted portion 36 so that themember normally assumes the position as shown in Figure 4 for movementto the position as shown in Figure 3 by the engagement of the lug 21therewith so that the forward rounded end 01 mounted within the bore 08of the plug 99 will move the-block I00 to the lowermost position andagainst the action of the springs I05 which hold the pin through itshead I03 upwardly within the bores I04, so that the safety block I00will move to assume the position as shown in Figure 4. Thus, should ashell remain within the breech of the barrel, the introduction of a newcartridge therewithin will be prevented and the mechanism will be lockedagainst further movement. In the construction illustrated in Figures 15,16, 17, and 18, a modified arrangement of scar is shown mounted at thetop of the receiver covered by the lid I06. This comprises a doublelever I01 mounted in place by means of the pin I08 between the ears I09thereof, and mounted in the forward end thereof, in the recess III, andheld against upward displacement by means of the plate I I I, is a catchor bolt I I3 propelled downwardly by means-of the spring I I2 forengagement with theedge II 4 of the sear 2I' of the firing pin. Also, toassist in moving the lever I31 from locked position, as shown in Figure15, to released position, as shown in Figure 16, in the free end of thelever I01 two pins II5 are carried, which pins are spring-propelled bymeans of the spring II 1 so that their lower ends will engage the upperportion of the lugs II5 carried by the locking bolt 30'. Thus, it willbev seen that when the locking bolt is elevated into breech-lockingposition, the members I I5 will engage the pins H5 and thusautomatically elevate the free end' of the lever I01 so as torelease'the firing pin,

In order to provide a means whereby this release may be performedmanually, the rear end I IQ of the lever I I1 is adapted to be "engagedby the portion I20 of the sliding bolt H8 mounted abovethe receiver andwithin the rear end of the lid I05. This is accomplished through theinstrumentality of the slot I2I and the head I22 of the bell-crank leverI23, which lever is mounted upon the pin I24 between'the projections I25of the receiver and is manually operated through the pin clearly shownin Figures'l9 and 20 in which a lever I23 with a hand-piece I is mountedfor pivotal and sliding movement through the instrumentality of the slotI3I and pin I32 at the right-hand rear side of the receiver. its forwardhooked end I34 being disposed to be projected through the opening Iagainst the spring I36 so as to engage the hook I31 attached to theblock 2|" ofthe firing pin I1. By this means,

the firing pin may be movedfrom the position;

I31. This operation may be repeated any number of times.

In the construction of muzzle dissipater shown in Figures 1, 21 and 22,the outer casing I30 is providedzwith a central tube 'I3I which acts asa; guide for the bullet with perforations I32 therethrough, said tubeproviding a chamber I34 at the inlet end outletting at the periphery I35between the outer edge of the spiral I36 and the inner face of thecasing I30. Thus, the gases emitting from the muzzle are directed intothe chamber at the inner end thereof, and are diffused through thespiral chamber, the perforations of the tube and the tube so as to actasa brake at the muzzle of the gun.

By having the spiral disconnected at the pe riphery with the inner wallsof the chamber, collection of carbon or dirt is prevented, and'th'esame'is finally carried out through the outlet 1 of the dissipater.

As shown in Figure 15 of the drawings, themember 5', as the bolt 30" iselevated into locking uosition at the rear of the breech block I3" andafter the final locking of the same, engages the free end of the leverI01, and thus releases the sear so that the firing pin is released toexplode the fulminating cap. This particu lar construction dispenseswith the link I21 and the parts operated thereby.

' I claim:--

1. A machine-gim including a receiver, a barrel connected thereto, abreech block reciprocatingly' mounted within the receiver for straightline'movement to and from the breech of the barrel, a spring propelledfiring pin bodily carriedby the breech block, a fixed locking membermounted in the receiver, a vertically movable lock bodily carried by thebreech block for cooperation with the fixed member when the breech blockis in breech-closing position, means for retracting the firing pinduring the closing of the breech, the same being released to freethefiring pin by the movable look as the latter completes its f finallocking movemeniyand a device-connected tothe breech block for causinglimitedv sliding movement of the movable lock, whereby the lockis'released before the breech block is started on its rearward movement.

2. Amachine-gun including a receiver, a barrel connected thereto, abreech block reclprocat-. .ingly mounted within the receiver forstraight line movement to and from the breech of the barrel, a springpropelled firing pin bodily carried by the breech block, a fixed lockingmember mounted in the receiver, a vertically movable lock bodily carriedby the breech block for cooperation with the fixed member when thebreech block is in breech-closing position, and a device connected tothe breech block for causing limited sliding movement of the movablelock,whereby the lock is released before the breech block is started onits rearward movement, gas-set and spring-actuated means mounted in thereceiver and connected to said breech block for imparts ing rearwardmovement to the breechblock, means mounted in the receiver and in thepath to engage and set the firing pin as the breech block ismoved in toclosing position, said'means oeing released by the movable lock whensaid lock is moved into final locking position, and a spring compressedduring said rearward move- .ment to impart forward and closing movementto the breech block after releasing of the first r I I 3. A'machine-gun, including a receiver, a bar I second spring to setthe'same. I v

5. A machine-gun, including a receiver, abar-. rel connected thereto, abreech block reciprocatinglymounted within the receiverIorstraightline'movement to and irom the breech of the 1 barrel, a fixedlockingmember mounted in' the receiver, a movable lock bodilycarried bythebreech block for cooperation with the fixed lc ick-k ing'member whenthe breech block is in breech closing position, gas-set and.spring-actuated; means connected to said bree'ch block for impartingrearward movement'to thebreech, block, a; spring compressed duringrearward {movement to impart forward and closing movement to, the thefirst spring, inv prevent the closing of a misfire and ,a spentcartridge. shell remains in the breech of. thebarrel.' .55

spring-propelled firing pin "carried bodily .byz th I lockforjreleasingthe firing pin M I ingot the breech block, and manuallycontrolled I ingly mounted within the receiver forstraightlinemovementto and from the 'breechotthe barrel, a fixed lockingmember mounted'in the receiver, a movable lock bodily carried byfthe;

breech block for cooperation with the fixed'lo'cking member when thebreech block lain breechclosing position, i gas-set spring;actuatedmeans connected to said breech block 'forimparting rearward movement tothebreechiblock,

a spring compressed during rearward movement to impart forwardandiciosing movement to I the breech block after release'of thefirstispring, a spring-propelled firing pin carriedbodily by the breechblock, means for coincidentally setting the firing pin at the close ofthe breech by the breechblock, and means carried by the movable -memberof the lock vi'or'releasing the same at the final locking of the breechblock.

4. A machine-gun, including a receiver, a barlinegmovement 'to andfrom'the breech ofthe barrel, a fixed'locking member mounted in themeans connectedto said breech block for imparting rearward movement tothe breech block, a spring; compressed during rearward movement toimpart forward and closing movement tothe breech block afterrelease ofthe first-spring;

manually operated means is provided for moving' the breech block againstthe action of the breech block after release of which means is providedto, of the breech block in case 6. Amachine-gun including a.receiver, a-,b arfrel connectedthereto, a breech block.reciprocatreceiver, forstraight I H v recoil actionto thefgilni 7 .l3.- Anautomatidgunaccording to claim 1, in

barrel, a fixed locking member'mounted infthe' receiver, a movable Ilock bodily carriedfbfth breech block for cooperation withthefixedjnieher when the breech block is in breech-clo'sin position, gas-set andspring-actuated means'cdn-' nected' to said breech jblock compressed'during said rearward *mover-n ntTt impart forward and closing breechblock after release of the first spring,

breech block, means. for ,coincidentailyfisett means c'arried by themovable member-crime at thefinal ack;

for setting and, releasing, the" recoilactlon tothe'gun; a l

' powder curve is vat its maximum, ,returned plunger mounted in the tubeand oper- V I r for imparting 'jreare wards movement to the'breechblockia sp ng' movement" ohe after the "same has, been automaticallyreleased and the breech block is still in locked position.

*7. 'A machine-gun according to claim 6 in which there is provided ameans for locking the breech blockagainst closing action due to theretention inthe breech of a deformed cartridge casing.

from the breech of the barrel, a locking member carried by the receiver,a slidable locking member carriedby the breech block, and cooperatingmeans carried by the slidable locking member and plunger-'actuatedirodfor imparting vertical reciprocatingmovement'to the locking memberduring the locking and unlocking of. the breech block.

91A machine-gun according toclaim 8 in which there is a spring iopposingthe rearward movement of the breechblockiand for propelling the breechblock into breech-closing position and for moving -me locking membercarried thereby into "locking position, av firing pin'carried by thebreech block; meansdis posed in the path of the firing pinfor'settin'g'the same during the closing of the'breec'h'block, and meanscarried by' 'the movable locking member for releasing the firing pinwhenthe breech block is fully locked.

.10. An automatic gun according to claim 1, in which there isatubewdisposed parallel with the barrel'and in communication with-thebore of the'barrel at a pointwhere the ordinate of the powder curve isat its" maximum, and a spring returned plunger mounted in'the tube andoperated in aforwarddirection by the gases of explosion admitted tothetube to produce a counter- 11. automatic' gun'according to claim 6, in

hich there is a 'tlibe disposed parallel with the barrel" andincom'munic'ation with the bore of the barrel at a point'where' theordinate oi the and a spring atediina' forward'direction by thegases ofexplosion admitted to thetubetoproduce a counter- V recoil action tothe'g'gu'n 12. An automaticgun according to claim. 8, in

J which there is. a, tubeqdisposedfparallel with the barrel and-lncommunication with the bore of the barrel at a point where the ordinateof the powder curve isjatf-its' maximum, and a spring returned plungermountedin' the tube and operatedin 'a'forward'I-direction byfthe gasesof explosicn'a'dmitted-to the tube to producea counterwhich'lthere isa'tube disposed parallel with the the.

powder. curve; is at its maximum, a spring returned plunger mounted inthe tube and operated in' ai forward direction by the gases of explosionthe muzzle of the barrel'and upon which the gases-of" explosion actincooperation with the plunger to produce a counterrecoil action to the 8J i [14. An automati'c gun according to claim 6, hichith'ere is -a' tubedisposed parallel with e. 'barrel and in jcommunication with the bore0i' the barrel; at'apoint where the ordinate of theipowder curvei's'at'its maximum, a spring revbarrel "andQin:{communication with thebore' of I barrelat a point-where the ordinate of the admitted to'thewas, and a braking device at in the receiver for "straight line movementto and turned plunger mounted in the tube and operated in a forwarddirection by the gases of explosion admitted to the tube, and a brakingdevice at the muzzle of the barrel and upon which the gases of explosionact in cooperation with the plunger to produce a counterrecoil action tothe gun.

15. An automatic gun according to claim 8, in

which there is a tube disposed parallel with the barrel and incommunication with the bore of the barrel at a point where the ordinateof the power curve is at its maximum, a spring returned plunger mountedin the tube and operated in a forward direction by the gases ofexplosion admitted to the tube, and a braking device at the muzzle ofthe barrel and upon which the gases of explosion act in cooperation withthe plunger to produce a counterrecoil action to the gun.

16. A machine-gun including a receiver, a barrel connected thereto, abreech block reciprocatingly mounted in the receiver for straight linemovement, a fixed locking member mounted in the receiver, a movable lockbodily carried by the breech block for cooperation with said fixedmember when the breech block is in breechclosing position, gas-set andspring actuated means connected to said breech block for impartingrearward movement to the breech block, a spring compressed during saidrearward movement to impart forward and closing movement to the breechblock at the release of the first spring, a spring propelled firing pincarried bodily by the breech block, means for coincidently setting thefiring pin at the closing of the breech, and means carried by themovable member of the lock for releasing the same at the final lockingof the breech block.

17. A machine gun according to claim 16, in which there is provided ameans for locking the breech block against closing action due to theretention in the breech of a deformed cartridge casing or a misfire.

18. A machine gun according to claim 16, in which there is a tubedisposed parallel with the barrel and in communication with the bore ofthe barrel at a point where the ordinate of the powder curve is at itsmaximum, and a spring returned plunger mounted in the tube and operatedin a forward direction by the gases of explosion admitted to the tube toproduce a counterrecoil action to the gun.

19. An automatic gun, including a receiver, a barrel attached thereto, abreech block mounted in the receiver for movement to and from the breechof the barrel, a spring propelled firing pin carried by the breechblock, a gas-set and spring returned plunger mounted adjacent to thebarrel, means for determining the amount of power stored in the springindependent of variation of powder pressure, a rod mounted forreciprocation within the receiver, and cooperative means carried by therod and the breech block whereby the breech block and rod are permittedindependent forward movements and whereby the rod will move the breechblock rearwardly when the plunger and rod are spring propelled, andmeans for setting the firing pin mounted in the receiver, the latterbeing released at the final closing of the breech block.

20. An automatic gun according to claim 19, in which a tube is disposedparallel to the barrel and has a port in communication with the barrel,the plunger being mounted in the tube, said port being at a point wherethe ordinate of the powder curve is at its maximum.

21. An automatic gun, including in combination a receiver. a' barrelattached, thereto, a breech block mounted in the receiver for straightline movement, a spring propelled firing pin carried by the breechblock, means for reciprocating 5 the breech block, means carried by thereceiver in the path of the firing pin for setting the same as thebreech block is moved into breech closin position, and means carried bythe breech block for engaging the setting means to release the firingpin.

22. An automatic gun as claimed in claim 21, in which manually operatedmeans is provided for retracting and releasing the firing-pinindependent of movement of the breech-mechanism.

23. An automatic gun as claimed in claim 21, in which means is providedfor preventing the closing of the breech block and the introduction of anew cartridge in the breech of the barrel should a portion of a spentshell or a spent shell remain in the breech of the barrel.

24. In a gun, a receiver, a bolt, and locking and shifting means for thebolt in the receiver including a locking member, means for moving thelocking member to operating and inoperating positions, said means havingan inclined slotted connection with the locking member permitting thelock to have a movement independently of the bolt, but at apredetermined position upon shifting the bolt in one direction, andother means for forcing the bolt in the reverse direction whereby theslotted connection is maintained under pressure to hold the lock inretracted position to prevent movement thereof in a locking direction.

25. In a gun, a receiver, a bolt, and locking and shifting means forthebolt in the receiver mcluding a locking member, means for moving thelocking member to operating and inoperating positions, said means havingan inclined connection with the locking member permitting the lock tohave a movement independently of the bolt, but at a predeterminedposition upon shifting the bolt in one direction, and other means forforcing the bolt in the reverse direction whereby the connection ismaintained under pressure to hold the lock in retracted position toprevent movement thereof in a locking direction.

26. In a gun, a receiver, a bolt, and locking and shifting means for thebolt in the receiver including a locking member, means for moving thelocking member to operating and inoperating positions, said means havingan inclined loose connection with the locking member permitting the lockto have a movement independently of the bolt, but at a predeterminedposition upon shifting the bolt in one direction, and other means forforcing the bolt in the reverse direction whereby the loose connectionis maintained under pressure to hold the lock in retractedposition toprevent movement thereof in a locking direction, the arrangement of theparts permitting the lock actuating means to operate under momentum whenthe bolt has been positioned in its return movement to move the lockinto locking position relative to the bolt.

27. In a gun, a bolt having a straight line movement, means foractuating the same, and means for locking the bolt against movementcomprising a locking member movable in a rectilinear path to have asubstantial bearing at right angles to its longitudinal axis andsubstantially in line with the center of load to be applied thereto.

28. In a gun, a bolt having a straight line 7 movement, means foractuating the same, and means for locking the bolt against movementcomprising a locking member movable in a rectilinear path to have asubstantial bearing at right angles to its longitudinal axis andsubstantially in line with the center of load to be applied thereto, therear face of the lock being wedge-like to crowd the bolt home when thelock is forced into locking position.

29. An automatic gun including a receiver, a breech block mounted formovement in the receiver, a movable locking member for locking thebreech block in closed position, a spring-propelled firing-pin carriedby the breech block, means for setting the firing-pin at the cloflng ofthe breech block, said lock releasing the firing pin upon locking of thebreech block, and means for manually controlling the releasing of thefiringpin independent of the locking of the breech block.

30. An automatic gun including a receiver, a breech mechanism mountedfor reciprocating movement in the receiver, means for moving the breechmechanism to the rear, other means for moving the breech mechanismforwardly, a spring-urged firing-pin carried by the breech mechanism,means for setting and releasing the firing-pin upon closing of thebreech mechanism, means for manually controlling the releasing of thefiring-pin, and a manually controlled sear for engaging the breechmechanism when in its rearward position to hold the breech mechanismopen.

31. An automatic gun including a receiver, a breech mechanism mountedfor movement in the receiver, a spring-urged firing-pin carried by thebreech mechanism, means for setting and releasing the firing-pin uponclosing of the breech mechanism, means for reciprocating the breechmechanism to cause automatic operation of the gun upon the firing of acartridge, means for manually controlling the releasing of thefiringpin, and a manually controlled member for catching and holding thebreech mechanism when in its rearward position.

32. An automatic gun including a receiver, a barrel attached to saidreceiver and having a gas port adjacent the breech end thereof, a breechmechanism movably carried in said receiver, piston means actuated in aforward direction by gases from said port, and power storage andcounter-recoil abutting instrumentalities including the gas actuatedpiston means, a spring adapted to be compressed under the actuation ofsaid piston means for storing power to operate said breech mechanism. acounter-recoil abutment fixed forwardly to the gun, means for eifectinga positive abutting relationship between the piston means and theabutment at the final stroke of the piston means, said abutment beingsubstantially non-resilient and non-recovering so as to transmit to theted parts of the gun the forward force of the piston means which is in adirection opposite to the recoil force of the gun.

33. In an automatic gun having a barrel, shell ejecting and re-loadingmechanism, piston means associated with said m to actuate the same, acylinder attached to said barrel and in communication therewith toreceive gas therefrom, resulting from the explodon of a power charge, anabutment secured to said cylinder and energy storing means in saidcylinder means, said piston and cylinder means and energy storing meansbeing so related in said gun that said powder gases actuate said pistonmeans forwardly of the gun-and transmit energy to said energy storingmeans, said energy storing means thereafter furnishing the energy toactuate the piston means and said mechanism; the combination of asubstantially non-resilient abutment means between said aforementionedabutment and said piston means to limit the amount of energy stored insaid energy storing means and whereby the excess energy will besubstantially all transmitted to said gun in a forward direction.

ROBERT F. HUDSON.

